/* ---------- Design tokens ---------- */
:root {
  --bg: #FCFCFD;
  --bg-elevated: #FFFFFF;
  --bg-subtle: #F4F4F6;
  --border: #E6E6EB;
  --border-strong: #D4D4DC;
  --text: #1A1A22;
  --text-muted: #6B6B7B;
  --text-faint: #A0A0AC;
  --accent: #5B5BD6;
  --accent-hover: #4747C2;
  --accent-tint: #EEEEFB;
  --shadow-sm: 0 1px 2px rgba(20, 20, 40, 0.04);
  --shadow-md: 0 4px 16px rgba(20, 20, 40, 0.06);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --header-h: 56px;
  --footer-h: 32px;
  --font-ui: -apple-system, BlinkMacSystemFont, "Inter", "Segoe UI", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", "SF Mono", ui-monospace, "Menlo", monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0E0E12;
    --bg-elevated: #16161C;
    --bg-subtle: #1C1C24;
    --border: #2A2A33;
    --border-strong: #3A3A45;
    --text: #ECECF1;
    --text-muted: #9898A6;
    --text-faint: #5F5F6E;
    --accent: #7B7BE6;
    --accent-hover: #9090F0;
    --accent-tint: #1F1F35;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
  }
}

/* ---------- Reset & base ---------- */
*, *::before, *::after { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-ui);
  font-size: 14px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body {
  display: grid;
  grid-template-rows: var(--header-h) 1fr var(--footer-h);
  height: 100vh;
  overflow: hidden;
}

button { font: inherit; color: inherit; cursor: pointer; }
input, textarea { font: inherit; color: inherit; }

/* ---------- Header ---------- */
.app-header {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 16px;
  padding: 0 20px;
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
  height: var(--header-h);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  font-size: 15px;
  letter-spacing: -0.01em;
}

.logo-mark {
  width: 26px;
  height: 26px;
  flex-shrink: 0;
  filter: drop-shadow(0 2px 4px rgba(91, 91, 214, 0.25));
  transition: transform 200ms cubic-bezier(0.34, 1.56, 0.64, 1);
}
.brand:hover .logo-mark {
  transform: translateY(-1px) rotate(-2deg);
}

.logo-word {
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.015em;
}

/* Theme switcher */
.theme-switcher {
  display: inline-flex;
  background: var(--bg-subtle);
  border-radius: var(--radius-md);
  padding: 3px;
  border: 1px solid var(--border);
}

.theme-chip {
  border: 0;
  background: transparent;
  padding: 6px 14px;
  border-radius: 7px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-muted);
  transition: color 120ms ease, background 120ms ease, box-shadow 120ms ease;
}

.theme-chip:hover { color: var(--text); }

.theme-chip[aria-checked="true"] {
  background: var(--bg-elevated);
  color: var(--text);
  box-shadow: var(--shadow-sm);
}

/* Action buttons */
.actions {
  display: flex;
  gap: 8px;
  justify-content: flex-end;
  align-items: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  border-radius: var(--radius-md);
  font-size: 13px;
  font-weight: 500;
  border: 1px solid transparent;
  transition: background 120ms ease, border-color 120ms ease, color 120ms ease, transform 80ms ease;
  white-space: nowrap;
}

.btn:active { transform: translateY(1px); }

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  pointer-events: none;
}

.btn-ghost {
  background: transparent;
  border-color: var(--border);
  color: var(--text);
  cursor: pointer;
}
.btn-ghost:hover {
  background: var(--bg-subtle);
  border-color: var(--border-strong);
}

.btn-primary {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
  box-shadow: var(--shadow-sm);
}
.btn-primary:hover { background: var(--accent-hover); border-color: var(--accent-hover); }

/* ---------- Workspace (split) ---------- */
.workspace {
  display: grid;
  grid-template-columns: 1fr 1px 1fr;
  height: 100%;
  overflow: hidden;
  background: var(--bg);
}

.pane {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-width: 0;
}

.pane-editor { background: var(--bg-elevated); }

#editor {
  flex: 1;
  width: 100%;
  border: 0;
  outline: 0;
  resize: none;
  background: transparent;
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 13.5px;
  line-height: 1.6;
  padding: 28px 32px;
  tab-size: 2;
}

#editor::placeholder { color: var(--text-faint); }

.splitter {
  background: var(--border);
  cursor: col-resize;
  transition: background 120ms ease;
}
.splitter:hover, .splitter:focus-visible { background: var(--accent); outline: none; }

.pane-preview {
  background: var(--bg);
  overflow-y: auto;
}

/* Preview gets scoped theme styles from themes/*.css.
   This is the outer container only — the typographic system lives in the theme files. */
.preview {
  max-width: 780px;
  margin: 0 auto;
  padding: 48px 56px;
  min-height: 100%;
}

/* ---------- Drag & drop overlay ---------- */
.drop-overlay {
  position: fixed;
  inset: 0;
  background: rgba(20, 20, 40, 0.4);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  animation: fade-in 120ms ease;
}

.drop-overlay[hidden] { display: none; }

.drop-overlay-card {
  background: var(--bg-elevated);
  border: 2px dashed var(--accent);
  border-radius: var(--radius-lg);
  padding: 48px 64px;
  text-align: center;
  box-shadow: var(--shadow-md);
}

.drop-overlay-icon {
  font-size: 36px;
  color: var(--accent);
  margin-bottom: 12px;
  animation: bob 1.2s ease-in-out infinite;
}

.drop-overlay-card p {
  margin: 0;
  font-size: 15px;
  font-weight: 500;
}

.drop-overlay-card code {
  background: var(--accent-tint);
  color: var(--accent);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 13px;
}

@keyframes fade-in { from { opacity: 0; } to { opacity: 1; } }
@keyframes bob { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(4px); } }

/* ---------- Footer ---------- */
.app-footer {
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-elevated);
  border-top: 1px solid var(--border);
  color: var(--text-faint);
  font-size: 12px;
  height: var(--footer-h);
}

/* ---------- Responsive ---------- */
@media (max-width: 760px) {
  .workspace { grid-template-columns: 1fr; grid-template-rows: 1fr 1px 1fr; }
  .splitter { cursor: row-resize; }
  .app-header { grid-template-columns: 1fr; grid-template-rows: auto auto auto; height: auto; padding: 12px 16px; gap: 8px; }
  .actions { justify-content: center; }
  body { grid-template-rows: auto 1fr var(--footer-h); }
  .preview { padding: 24px 20px; }
}

/* ---------- Focus styles ---------- */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 4px;
}